Ob
Ob is a mapped river in the YearMaps hydrographic index. River courses organise settlement, agriculture and frontier-making more durably than any political boundary, and this reach is indexed against the dams, lakes and cities within its catchment.
- Feature Class
- River
- Coordinates
- 59.61°, 79.21°

About Ob
The Ob (; Russian: Обь) is a major river in Russia. It is in western Siberia, and with its tributary the Irtysh forms the world's seventh-longest river system, at 5,410 kilometres (3,360 mi). The Ob forms at the confluence of the Biya and Katun which have their origins in the Altai Mountains. It is the westernmost of the three great Siberian rivers that flow into the Arctic Ocean (the other two being the Yenisei and the Lena). Its flow is north-westward, then northward.
The main city on its banks is Novosibirsk, the largest city in Siberia, and the third-largest city in Russia. It is where the Trans-Siberian Railway crosses the river.
The Gulf of Ob is the world's longest estuary.
Encyclopedic summary adapted from Wikipedia: Ob (CC BY-SA 4.0).
Ob in Depth
Geography
The Ob forms 25 km (16 mi) southwest of Biysk in Altai Krai at the confluence of the Biya and Katun rivers. Both these streams have their origin in the Altai Mountains, which gradually give way to the Ob Plateau. The Biya has its sources in Lake Teletskoye and the 700 kilometres (430 mi) long Katun in a glacier on Mount Byelukha.
The Ob itself is in Russia. Its tributaries extend into northern Kazakhstan, a western corner of China and a tiny upland parcel of the western tip of Mongolia, where the wider borders match the drainage basin almost precisely. The river splits into more than one arm after the large Irtysh flows into it at about 69° E. Originating in China, the Irtysh is the furthest source of the Ob.
Tributaries
Smaller tributaries include Pemboy (right), 207 km off the mouth of the Ob.
In addition, the Nadym and the Pur River flow into the Gulf of Ob and the Taz into the Taz Estuary, a side arm of the Gulf of Ob.
Sections adapted from Wikipedia: Ob (CC BY-SA 4.0).
Ob: Key Facts
| Length | 3,650 km |
|---|---|
| Average discharge | 12,492 m³/s |
| Drainage basin | 2,990,000 km² |
| Source | Katun |
| Mouth | Kara Sea |
| Drainage system | Ob Basin |
| Tributaries | Irtysh, Vasyugan, Ket, Tom, Tym, Vakh, Chulym, Poluy |
Facts from Wikidata Q973 (CC0).
Major River Dossiers
Hand-written studies of the great river systems of history.
Connected Reaches
Nearby watercourses in the same drainage network.
Water Bodies in the Catchment
Settlements Along the Reach
Hydraulic Infrastructure Nearby
Surrounding Terrain
Ob: Quick Answers
- Where is Ob?
- Ob is located in Russia, at 59.6068° N, 79.2115° E.
- Are there dams on the Ob?
- No dam on the Ob is recorded in the YearMaps dam index, which covers major structures only.